Malignant tumors are diseases that seriously threaten human life and health, searching for an effective therapy with less toxic side effects has became the most important medical research in recent years. According to the principle of enantiopathy, using viruses to kill tumor cells is an ideal strategy for cancer treatment. However, this strategy faces two problems: how to make viruses selectively reach tumor site and how to make viruses escape from body's immune system attack.
Viral DNA or RNA is assembled with proteins and other biomolecules to form viral particle, which can infect tumor cell and replicate in large quantities in tumor cell to produce new virus particles and eventually cause lysis of the tumor cell, i.e. it is so-called oncolytic virus, i.e. tumor-killing virus capable of replicating. However, oncolytic viruses as alien components will be immunologically rejected by the body upon entry into the body, in particular, the production of antiviral antibodies can limit the antitumor effect of oncolytic viruses through clearance of the viruses. In addition, free oncolytic viruses easily access into normal tissues, which not only weaken the effective killing effect of viruses on tumor cells, but also cause damage to normal tissues, and generate toxic side effects.